JPH0442357B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides a method for producing mixed fertilizer granules, and more specifically,
This invention relates to a mixed fertilizer granule of powdered dissolved phosphorous fertilizer and powdered silicic acid fertilizer. In recent years, with the modernization of agriculture, a method of mechanically distributing a bulk blend of several types of fertilizers has been used to save labor in fertilization, but this method is only intended for granular fertilizers. Classification is severely inapplicable to so-called fine-grained fertilizers such as dissolved phosphorous fertilizers and siliceous fertilizer mixtures. Therefore, several methods of granulating dissolved phosphorous fertilizers and siliceous fertilizer mixtures have been attempted, and various binders have been proposed. Examples include granulation by using valve waste liquid, granulation by mixing the waste liquid with bentonite, urea, nitrofumic acid, alcohol fermentation waste liquid solids, and bentonite. In addition, granules are required that have sufficient strength to withstand transportation, storage, etc., appropriate apparent specific gravity, do not generate dust, and have a good texture. Regarding granulation, it has been developed to obtain granulated products using mainly organic by-products such as alcohol fermentation waste liquid as a binder. However, when granulation is performed using such by-products, the production volume of the main product tends to be controlled, so not only is the supply not stable, but the quality is also likely to vary. In addition,
By-products such as alcohol fermentation waste liquid have a strong odor, putrefaction, and high BOD content, which not only deteriorates the working environment but also requires the cost of BOD removal. In view of the above problems, the present inventors conducted research to obtain a granulated product that is more industrially advantageous, and surprisingly discovered that magnesium sulfate is an excellent binder, and completed the present invention. . That is, the present invention provides a method for producing mixed fertilizer granules comprising a mixture of powdered dissolved phosphorous fertilizer and powdered silicic acid fertilizer and a binder, in which the powder mixture has a specific surface area of 500
~3000cm ² /g, 10 to 60% by weight of particles with a particle size of 44 μm or less, and an appropriate amount of water to a blend of 100 parts by weight of the powder mixture and 1 to 7 parts by weight (calculated as MgSO ₄ ) of magnesium sulfate-containing material as a binder. The present invention relates to a method for producing a mixed fertilizer granule, which is characterized by adding granules, granulating the mixture, and drying the mixture at 70 to 120°C. The powdered fertilized phosphorus fertilizer applied in the present invention is no different from that commonly used, and is made by mixing phosphate rock and magnesium silicate minerals such as serpentine rock, peridotite, or smelted nickel in a predetermined ratio. It is a glassy powder obtained by heating and melting a mixture, then rapidly cooling it with water, etc., and pulverizing it. In this case, trace elements such as boron, manganese, copper, zinc, or molybdenum may be present in the melted phosphorous fertilizer as necessary. In addition, the powdered siliceous fertilizer applied in the present invention is generally called silicic acid or magnetic silicic acid, and contains soluble silicic acid, alkali content, soluble magnesium, etc. Raw materials include slags, stainless steel slags, ferromanganese steel slags, silicomanganese slags, ferronitkel slags, nickel slags, ferrochrome slags, magnesium slags, and phosphorus production slags. The particle size and specific surface area of the mixture of powdered dissolved phosphorous fertilizer and powdered silicic acid fertilizer, together with the properties of the binder used, significantly affect the physical properties when granulated, so it is necessary to adjust them within a predetermined range. However, in the present invention, the above two powdered fertilizer mixtures have a specific surface area of 500 to 3000 cm ² /g and a particle size of 500 to 3000 cm 2 /g.
It is most preferable to have a content of 10 to 60% of 44μ or less; outside this range, it tends to be difficult to satisfy the contradictory property requirements of water disintegration and granulation strength. Next, in the present invention, in granulating the above two powdered fertilizer mixtures, a substance containing magnesium sulfate is used as a binder, but this is not only industrial magnesium sulfate, but also the reaction between magnesium hydroxide and sulfuric acid. products, reaction products of magnesia and sulfuric acid, reaction products of serpentine or peridotite and sulfuric acid, etc. are mainly composed of MgSO ₄ but also contain some MgCl ₂ , Mg (OH) ₂ may be included. Therefore, even if a certain amount of unreacted magnesium etc. is mixed in due to its nature, it can be used without any problem as long as it substantially contains magnesium sulfate. It may be of. The amount of magnesium sulfate-containing substances used in mixed fertilizers of powdered fused phosphorous fertilizer and powdered silicic acid fertilizer varies depending on manufacturing conditions and the physical properties of the mixture, but in most cases it is per 100 parts by weight of the powdered mixture. ,
1 to 7 parts by weight as _MgSO4 , preferably 2 to 4 parts by weight
A range of parts by weight is appropriate. The reason for this is that if it is less than 1 part by weight, granulation becomes difficult, while if it is more than 7 parts by weight, it is not only uneconomical but also causes problems in terms of balance with the fertilizing ingredients. To granulate the above two powdered fertilizer mixtures using the magnesium sulfate-containing material, conventional granulation methods can be used without particular limitation, such as a dish granulator, a drum granulator, or a compression molding machine (press granulator). ), etc., to granulate it while adding an appropriate amount of water, then dry it at a temperature of 70 to 120°C until it becomes a substantially dehydrated product, and if necessary, classify it to produce a product. . In addition, unless the above drying conditions are met, not only will it be impossible to obtain granules having the following predetermined particle size with a good yield;
This is because the granules do not have enough strength to withstand storage and transportation. The size of granules is not uniform depending on the purpose, but
In most cases, a range of 0.5 to 5 mm, preferably 1 to 4 mm is appropriate, and those outside this range are returned to the initial step and reused. Thus, according to the production method of the present invention, a mixture of powdered dissolved phosphorous fertilizer and powdered silicate fertilizer, which has conventionally been difficult to form into granules, can be made into a desired mixture by adjusting the particle size and using a magnesium sulfate-containing substance. It can be granulated to a size of In addition, the obtained mixed fertilizer granules are endowed with soluble magnesium and sulfate roots, can be blended with other fertilizers and applied mechanically, and have good water disintegration and soil disintegration properties. It is something. In addition, it has appropriate strength, apparent specific gravity, and good texture with no dust generation, and is more compliant with the Offensive Odor Prevention Act, Water Pollution Prevention Act, Soil Pollution Prevention Act, Industrial Hygiene Act, etc. compared to granulated products that use organic materials as binders. The present invention has great industrial significance because it can be manufactured without causing any problems in compliance with the various laws and regulations, and can be handled safely in use. Hereinafter, the present invention will be specifically described with reference to Examples. Examples 1 to 10 A mixture of the powdered dissolved phosphorus fertilizer and powdered silicic acid fertilizer shown in Table 1 was added with a predetermined amount of magnesium sulfate-containing material, and a mixture was prepared using a dish-type granulator (diameter 1000 m/m, depth 80 m). /m, rotation speed 12r.pm, inclination angle 54°) and spray with water until the particle size is 1~4mm (preferably 2mm).
3 mm). Dry this (70
~120℃) Moisture content should be 0.1% or less. After cooling, this product was sized to a particle size of 1 to 4 m/m, and this ratio was taken as the yield rate to obtain a mixed fertilizer granule of powdered melted phosphorous fertilizer and powdered silicate fertilizer. Table 1 shows the test results for average crushing strength, water disintegration, and soil disintegration for this product.
Shown below.

【table】

【table】

Claims (1)

[Claims] 1. In a method for producing mixed fertilizer granules comprising a mixture of powdered dissolved phosphorous fertilizer and powdered silicic acid fertilizer and a binder,
The powder mixture has a specific surface area of 500 to 3000 cm ² /g and a particle size of
10 to 60 parts by weight of particles of 44 μm or less, and granulate by adding an appropriate amount of water to a blend of 100 parts by weight of the powder mixture and 1 to 7 parts by weight (calculated as _MgSO4 ) containing magnesium sulfate as a binder, A method for producing mixed fertilizer granules characterized by drying at 70 to 120°C.